Systems for printing conformal materials on component edges at high resolution

ABSTRACT

Systems and methods that enable printing of conformal materials and other waterproof coating materials at high resolution. An initial printing of a material on edges of a component is performed at high resolution in a first printing step, and a subsequent printing of the material on remaining surfaces of the component is applied in a second printing step, with or without curing of the material printed on the edges between the two printing steps. The printing of the material may be performed by a laser-assisted deposition or using another dispensing system to achieve a high resolution printing of the material and a high printing speed.

RELATED APPLICATIONS

This application is a Divisional of U.S. application Ser. No.17/302,449, filed 3 May 2021 (now issued as U.S. Pat. No. 11,497,124),which is a nonprovisional of and claims priority to U.S. ProvisionalApplication No. 62/705,682, filed 10 Jul. 2020, and U.S. ProvisionalApplication No. 62/705,046, filed 9 Jun. 2020, each of which isincorporated by reference herein.

FIELD OF THE INVENTION

The present invention relates to systems and methods that enableprinting of conformal materials and other waterproof coating materialsat high resolution, for example at edges of a component.

BACKGROUND

For today's electronic products, reliability is critical. Consumersexpect dependable function, uninterrupted long-term use, and costeffectiveness. As a result, conformal coatings and encapsulationmaterials have been developed to meet the needs of most electronicdevices. Without these critical materials, the printed circuit boards(PCBs), which are arguably the foundation of all consumer electronics,would be susceptible to failure due to corrosion, high temperatures,moisture, vibration, and other environmental hazards. Conformal coatingmaterials protect PCBs and advanced substrates from thermal shock,moisture, corrosive liquids, and other adverse environmental conditions.Shielding electronic function from external influences ensures longproduct lives for harsh marine, automotive, medical, and consumerelectronics applications.

The use of conformal coatings is wide-spread in the electronicsindustry. However, many materials used in the field have a low surfacetension and the edges of the components are not covered well because ofa drift of the materials away from the edges of the components to itsrespective centers. Conventional deposition techniques will not resultin a covering of the edges unless a thick coating of material is used.But, a thick coating increases the overall temperature the component isexposed to during operation and thereby shortens the component's life.

SUMMARY OF THE INVENTION

In light of the foregoing shortcomings of conventional depositiontechniques for conformal coating, the present inventor has recognizedthe need for a solution that provides both deposition of the conformalcoating at a high resolution and that exposes the coating to ultraviolet(UV) curing gradually, beginning at the edges of the component first andproceeding to the rest of the coating material thereafter. The presentinvention provides, in various embodiments, a novel deposition techniquefor conformal coatings at a high resolution, initially directly on edgesof a component and thereafter on remaining portions of the component,with optional UV curing of the deposited coating material performedbetween the deposition steps.

In one embodiment of the invention, a conventional dispenser is used forthe edge deposition. In other embodiments, for example where heightdifference between components on a PCB provide difficulties when using aconventional dispenser, the conformal material is dispensed by way oflaser-induced jetting or laser-induced spraying. Conventional dispensersmay not be able to penetrate close enough to each component's edges and,as a result, a thicker conformal coating may be needed to ensure thatthe edges are adequately coated. To avoid the need for such a thickercoat, laser-induced jetting and/or spraying allows the coating materialto be transferred at a very high resolution from a relatively highdistance above the PCB (up to several mm) to the edges of the component.One example of a laser-induced jetting approach suitable for use inaccordance with embodiments of the present invention is disclosed inU.S. Pat. No. 10,144,034 by the present inventor and assigned to thepresent applicant.

In various embodiments of the invention, a material (e.g., a highlyviscous material, a wax material, a polymer material, a mix of a polymerand a monomer material, a heat or light sensitive low viscositymaterial, a material that can be cured by UV light or by heating, or amaterial that can be dried) is printed (e.g., using a laser-basedsystem) on edges of an electronic component to create a polymeric layerthereon and the material so printed is thereafter cured (e.g., by UVlight, heat, or both). Following curing of the material printed on theedges of the electronic component, a second printing of the materialover remaining portions of the component and curing of the materialapplied during the second printing takes place. In either or both of theprinting steps, printing may be performed using laser-induced jetting,laser-induced spraying, or both. For example, the material may beprinted as droplets jetted or sprayed from a layer of the materialcoated on a transparent or semi-transparent substrate.

The layer of the material may be coated on the transparent orsemi-transparent substrate by a coating system, for example one thatuses a well-defined gap between rollers or knifes to leave a uniformlayer of material on the substrate with a thickness that is defined bythe gap. Or, the coating system may be one that includes ascreen-printing module, a dispenser or an ink jet head, a gravure ormicro-gravure system, a slot-die system, a roller coating system, etc.In some cases, the coating system may be located inside a closed cellwith a controlled environment to prolong the pot life of the material.Also, the coating system may be configured to contain more than onematerial and to print a plurality materials onto the substrate in acontrolled sequence. During printing, the bottom surface of thesubstrate may be disposed at an acute angle with respect to a topsurface of the electronic component, and the electronic component may beinspected after each printing step (e.g., using a separate inspectionmodule or one that is integrated with the laser-based printing system).The droplets of material may vary in volume between the printing stepsand/or during individual ones of the printing steps.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is illustrated by way of example, and notlimitation, in the figures of the accompanying drawings, in which:

FIGS. 1 a and 1 b illustrate the use of a laser deposition system and acontact gap printing system, respectively, to print materials oncomponent edges, in accordance with embodiments of the presentinvention.

FIG. 1 c illustrates aspects of a coating system, in accordance withembodiments of the present invention.

FIG. 2 illustrates an example of incomplete edge covering by conformalmaterials printed using conventional, low resolution depositiontechniques.

FIGS. 3 a-3 e illustrate steps in a process of printing conformalmaterials at edges of a component in accordance with an embodiment ofthe present invention, in which FIG. 3 a illustrates an example of acomponent affixed to a PCB, FIGS. 3 b and 3 c illustrate materialdeposition on the component's edges and subsequent curing of thematerial so deposited, and FIGS. 3 d and 3 e illustrate materialdeposition on remaining areas of the component and subsequent curing ofthe material so deposited.

FIGS. 4 a-4 i illustrate steps in a process of printing conformalmaterials, in accordance with an embodiment of the present invention.

FIG. 5 illustrates aspects of laser induced spraying versus laserinduced jetting, either or both of which techniques may be employed inprocesses for printing conformal materials, in accordance with anembodiment of the present invention.

FIG. 6 a illustrates aspects of a system for printing conformalmaterials, in accordance with an embodiment of the present invention.

FIG. 6 b illustrates aspects of an in-line inspection module, inaccordance with an embodiment of the present invention.

FIG. 7 depicts components of a computer system in which computerreadable instructions instantiating the methods of the present inventionmay be stored and executed.

DETAILED DESCRIPTION

The present invention provides systems and methods for printingconformal materials (e.g., a polymeric material) 16 and other waterproofcoating materials at high resolution. In one embodiment of theinvention, the material 16 is a highly viscous material. In oneembodiment of the invention, the material 16 is a wax material. In oneembodiment of the invention, the material 16 is a polymer material or amixture of a polymer and a monomer material. In one embodiment of theinvention, the material 16 is a heat or light sensitive low viscositymaterial. In one embodiment of the invention, the material 16 is amaterial that can be cured by ultraviolet (UV) light or heat. In oneembodiment of the invention, the material 16 is a material that can bedried.

As shown in FIGS. 1 a and 1 b , systems configured in accordance withembodiments of the invention perform an initial printing on one or moreedges 13 of a component 18 affixed to a PCB 22 at a very high printingquality, and subsequently coat remaining areas of the component 18 in asecond printing step (shown in later figures), with or without curing ofthe material printed at the edges 13 of the component 18 between the twoprinting steps.

The component 18 may include an electronic component. More specifically,the component 18 may include an integrated circuit that has beenencapsulated in a protective package. For clarity, it is noted that thepackage of the integrated circuit may be distinct from the conformalcoating discussed herein. Edges 13 of a component 18 generally refer toa perimeter region of each planar (or substantially planar) surface ofthe component 18. The component 18 may be mounted to PCB 22 using aconductive material 20. The conductive material 20 may includepins/leads of an integrated circuit. The conductive material 20 may alsoinclude solder (e.g., solder balls, solder paste, etc.) used toelectrically connect respective terminals and/or pins/leads of theintegrated circuit to corresponding pads of the PCB 22.

In various embodiments, the material deposition may be performed bylaser assisted deposition (e.g., laser induced jetting and/or laserinduced spraying), or by another dispensing system to achieve a highresolution deposition of the material and at a high deposition speed.One example of a laser-induced jetting approach suitable for use as adeposition technique in accordance with embodiments of the presentinvention is disclosed in U.S. Pat. No. 10,144,034, incorporated hereinby reference.

Generally, in a laser-based printing system 11, a laser 10 (e.g., a highfrequency laser) is used to impart energy to a “tiny spot” (i.e., smallarea) on a transparent or semi-transparent substrate 12 that is coatedwith a layer 14 of the material 16. The energy from the laser 10dislodges a small portion (e.g., droplet) of the material 16, which isthen deposited (or printed) onto the component 18.

As shown in the side view of FIG. 2 , conventional, low resolutiondeposition of conformal coatings 17 (provided by low-resolutiondispenser 24′) often result in incomplete covering of edges of thecomponent 18. While the side view of FIG. 2 does not clearly show areasof edges 13 that are incompletely covered, it is understood that, in across-sectional view, there may be areas of edges 13 that areincompletely covered.

In contrast, the present invention provides very high resolutionprinting at the edges 13 of components 18, either through laser-assisteddeposition, as shown in the laser-based printing system 11 depicted inFIG. 1 a , or by use of a conventional high-resolution conformalmaterial dispenser 24 (e.g., an ink jet or other deposition system), asshown in FIG. 1 b . Conventional low-resolution dispensers 24′ may notbe able to penetrate close to a component's edges 13 and, as a result, athicker conformal coating may be needed to ensure that the edges 13 areadequately coated. To avoid the need for such a thicker coat,laser-induced jetting and/or laser-induced spraying (provided by thelaser-based printing system 11) allows the coating material to betransferred at a very high resolution from a relatively high distanceabove the PCB 22 (e.g., up to several mm) to the edges 13 of thecomponent 18.

As depicted in FIG. 1 a , laser-based printing system 11 may include acoating system 15 for applying a layer 14 of the material 16 withuniform thickness on a transparent or semi-transparent substrate 12.Additional aspects of the coating system 15 are illustrated in FIG. 1 c. In one embodiment of the invention, the coating system 15 may includea syringe 64 of the material 16 to be printed and an air or mechanicalpump that drives the material 16 onto the substrate 12. The substrate 12is then moved (e.g., using motors and gears/rollers 66) toward awell-defined gap 70 between rollers or knifes 72 of a coater 50 toremove excess material and create a uniform layer 14 of the material 16with a thickness that is defined by the gap 70. The material 16 is thentransferred from the substrate 12 to the component 18, e.g., usinglaser-assisted deposition (e.g., using laser 10 of laser module 54 tojet/spray portions of the material 16 from the substrate 12 towardscomponent 18).

In one embodiment of the invention, the coating system 15 includes ascreen-printing module wherein the material 16 is coated on a screen orstencil of film with well-defined holes and transferred to the substrate12 using a blade or a squeegee in a soft or hard engage. In oneembodiment of the invention, the coating system 15 includes a dispenseror an ink jet head to print the material 16 directly onto a carriersubstrate 12. In one embodiment of the invention, the coating system 15is a gravure or micro-gravure system that coats a substrate 12 with ahighly uniform layer 14, and the material 16 is then transferred fromthe substrate 12 to the component 18, as described above. In oneembodiment of the invention, the coating system 15 is a slot-die systemthat coats a substrate 12 with a highly uniform layer 14, and thematerial 16 is then transferred from the substrate 12 to the component18, as described above. In one embodiment of the invention, the coatingsystem 15 is a roller coating system that coats a substrate 12 with ahighly uniform layer 14, and the material 16 is then transferred fromthe substrate 12 to the component 18, as described above.

In one embodiment of the invention, the coating system 15 is locatedinside a closed cell with a controlled environment (cold or hot) toprevent evaporation of solvent from the printed material 16 or toprevent material oxidation, thereby prolonging the pot life of thematerial 16.

In some embodiments of the invention, the coating system 15 containsmore than one material, creating a possibility for printing a pluralityof materials onto the component 18 in a controlled sequence and makingit possible to print more than one material on the component 18.

In one embodiment of the invention, the substrate 12 used to transferthe material 16 to the component 18 may be translated bidirectionally ina controlled manner during the coating process (e.g., while opening thegap between the coater rollers), creating the possibility for recoatingthe same area of the substrate 12 with the material 16 multiple timeswithout contamination to the rollers. This recoating may reduce oreliminate the amount of substrate 12 consumed during the initialprinting process and prevent waste.

In one embodiment of the invention, the printing system may be alaser-based printing system 11 (as depicted in FIG. 1 a ) that containsa high frequency laser to enable jetting of the coated material 16 froma coated substrate 12 to the component 18 by laser-assisted deposition.Such as system may also be called a laser dispensing system. In oneembodiment of the invention, the printing system may be an ink jet headsystem (not depicted) that enables jetting a material 16 directly to thecomponent 18. In one embodiment of the invention, the printing systemmay be a dispenser head system (not depicted) that enables printing amaterial 16 directly to the component 18.

In one embodiment of the invention, a continuous transparent filmsubstrate is used as a substrate 12 for the printing system. That is,the transparent film substrate resembling a thin sheet of material inthe configuration of a loop (like an elongated rubber band) may bepassed over a series of rollers so that as one part is coated by coatingsystem 15, another part is disposed under the laser module 54 fordeposition. Eventually, the portion of the substrate 18 that has beendepleted of the coating material 16 will return to coating system 15 tobe recoated, and at a later point in time that recoated portion willagain be disposed under the laser module 54 for deposition. In oneembodiment of the invention, a transparent film substrate 12 coated by ametal layer or by a metal and a dielectric layer is used as a substrate12 for the printing system, e.g., in the manner described above.

As described in more detail below, the component 18 with the printedmaterial 16 covering one or more of its edges is exposed to UV light ordried by a heater after the first cycle of printing. In some embodimentof the invention, after printing remaining areas of the component 18 ina second printing cycle, the printed material 16 is further cured by UVlight or dried by a heater.

In some embodiments of the invention, the laser-based printing system 11creates a uniform layer of the printed material on the edge 13 of thecomponent 18, and that material is cured before the remaining portionsof the component 18 are coated. For example, FIG. 3 a showscross-sectional and perspective views of a component 18 mounted orotherwise affixed to a PCB 22 with conductive material 20. Morespecifically, the cross-sectional view in the left portion of FIG. 3 ais along cut-line I-I depicted in the perspective view in the rightportion of FIG. 3 a.

In the cross-sectional and perspective views of FIG. 3 b , edges 13 ofthe component 18 have been coated with a conformal material or otherwaterproof coating material 26. More specifically, the cross-sectionalview in the left portion of FIG. 3 b is along cut-line II-II depicted inthe perspective view in the right portion of FIG. 3 b.

In the cross-sectional and perspective views of FIG. 3 c , the material26 deposited over the edges 13 of the component 18 has been cured intocured material 28, e.g., by heating and/or by exposure to UV radiation(e.g., from a UV source such as one or more UV light emitting diodes(LEDs)). More specifically, the cross-sectional view in the left portionof FIG. 3 c is along cut-line III-III depicted in the perspective viewin the right portion of FIG. 3 c.

In the cross-sectional and perspective views of FIG. 3 d , the remainingportions of the component (along with some portions of a top surface ofthe PCB 22) have been covered by the conformal material 30 or otherwaterproof coating material. This deposition of material may beperformed using the same laser-based printing system 11 as was used forthe edge coatings (or using a different coating system). Morespecifically, the cross-sectional view in the left portion of FIG. 3 dis along cut-line IV-IV depicted in the perspective view in the rightportion of FIG. 3 d.

In the cross-sectional and perspective views of FIG. 3 e , the material30 deposited over the remaining portions of the component (along withsome portions of the top surface of the PCB 22) has been cured intocured material 32, again either by heating and/or by exposure to UVradiation. More specifically, the cross-sectional view in the leftportion of FIG. 3 e is along cut-line V-V depicted in the perspectiveview in the right portion of FIG. 3 e.

Referring now to FIGS. 4 a-4 h , an example of a process of printingconformal materials in accordance with an embodiment of the presentinvention is described. In the side and top views of FIG. 4 a , atransparent or semi-transparent substrate 12 has been coated with amaterial 16 (e.g., a polymeric material) or other waterproof coatingmaterial, that is to be applied as a conformal coating to a component 18located on a printed circuit board (PCB) 22. The material 16 to beprinted may be applied to the transparent or semi-transparent substrate12 in any of the manners described above. Once so applied, the substrate12 with the coated layer 14 of material is brought into proximity of thecomponent 18 with a laser printing head (depicted later in FIG. 6 a ),and the laser 10 is operated (e.g., in a pulsed fashion) to jet dropletsof the material 16 from the coated substrate 12 onto the edges 13 of thecomponent 18. In the view at right, a top view of the component 18 onthe PCB 22 is shown, with printed droplets of the waterproof coatingmaterial 16 around the edges of the component 18.

The volume of the droplets so printed may be determined by the energy ofthe laser 10 used for the jetting process, the thickness of the film 14of material coated on the transparent or semi-transparent substrate 12,or a combination of these parameters. In general, the size of theprinted droplet on the component 18 will be determined by its volume andthe vertical distance between the coated substrate 12 and the surface onwhich the droplets are printed. By controlling these parameters (e.g.,by varying the thickness of the coated layer 14, controlling the pulsewidth, pulse frequency, and/or number of pulses of the laser 10, and thespacing of the distance between the coated substrate 12 and the surfaceon which the droplets are printed), droplets of a desired size can beprinted on the component 18. Preferably, the droplet volume iscontrolled so as to ensure an even distribution of the coating material16 on the component 18. This may be easiest with droplets of commonvolume throughout the jetting process, but in some cases the dropletvolume may be varied during the jetting process, for example, whencomponent features demand or would benefit from the application ofdroplets of different volumes.

Referring briefly to FIG. 5 , in the present discussion and in theillustrations of FIGS. 4 a-4 i , laser-induced jetting is assumed.However, in some embodiments, laser induced spraying of the material 16from the coated substrate 12 may be used. With laser-induced spraying, aplurality of small droplets of the material 16 (versus a single, largervolume droplet as is produced in laser-induced jetting) are scatteredfrom the coated substrate 12 towards the component 18 on the PCB 22.Spraying in this fashion may be desirable in some instances. In somecases, a waterproof coating material 16 may be applied to a singlecomponent 18 and/or its associated PCB 22 using either or both oflaser-inducted jetting and laser-induced spraying. For example,laser-induced spraying may be employed when the waterproof coatingmaterial 16 is applied to the edges 13 of the component 18, whilelaser-induced jetting may be employed when the waterproof coatingmaterial 16 is applied elsewhere on the component 18 and/or the PCB 22.Jetting versus spraying of a waterproof coating material 16 may becontrolled or selected through variation of the pulse width, spot size,spot shape, pulse frequency, and/or number of pulses of the laser 10,the thickness of the layer 14 of coated material 16 on the transparentor semi-transparent substrate 12, or a combination of these parameters.Therefore, throughout the present discussion, reference to laser-inducedjetting, or illustration thereof, should be understood as including thepossibility of using laser-induced jetting alone, laser-induced sprayingalone, or a combination of laser-induced jetting and laser-inducedspraying both in a single process step or between process steps.

Returning to FIG. 4 a , once the edge or perimeter (or a desired portionof the perimeter) of the component 18 has been coated with the dropletsof the waterproof coating material 16, these droplets may be cured intocured droplets 38, as shown in the side and top views of FIG. 4 b . Insome embodiments, the curing may be performed via photopolymerization ofthe coated material using ultraviolet (UV) light 36 provided by a UVcuring module 34. Alternatively, or in addition, curing may be performedusing thermal radiation (heat), for example by placing the component 18and PCB 22 in an oven or under one or more heating (e.g., infrared)lamps, and/or using hot air flow from a blower. Still further, in someinstances, curing may be effected chemically, or by other means. Thiscuring step following the application of the waterproof coating material16 to the edges 13 of the component 18 is preferred, but is optional.Employing such a curing step has been found to enhance the overallconformal coating process. However, the use of such a curing step doesincrease the overall time to complete the coating process, so, in somecases, such curing step may be omitted in the interest of reducedoverall process time.

Following the curing of the waterproof coating material being applied tothe edges 13 of the component 18 (if such a step is employed), thecomponent 18 and PCB 22 are returned to the vicinity of the laserprinting head (depicted later in FIG. 6 a ) and, as shown in the sideand top views of FIG. 4 c , any gaps in the coated edge areas 13 of thecomponent 18 are printed in the same fashion as discussed above. Thatis, the substrate 12 with the coated layer 14 of waterproof material 16is brought into proximity of the laser printing head, and the laser 10is operated (e.g., in a pulsed fashion) to jet droplets of the material16 from the coated substrate 12 onto the edges 13 of the component 18 tofill in any gaps in coverage from the first printing step, and/or toapply an additional coat of the waterproof material 16 to the edges 13of the component 18. Then, as shown in the side and top views of FIG. 4d , another optional curing step may be employed to solidify (or cure)these newly printed droplets of the waterproof material 16 into a layerof cured material 38 over the edge 13 of the component 18.

Referring to FIG. 6 a , a block diagram of a system 46 configured forprinting conformal materials in accordance with an embodiment of thepresent invention is shown. As illustrated, the component 18 and PCB 22may be located on a moveable stage 42 (e.g., moveable in threedimensions) so as to be positionable and relocatable between the laserprinting head 45 and the curing module 34. It is understood that laserprinting head 45 may include the previously-described laser 10,substrate 12 and layer 14, in addition to mechanical components (e.g.,tracks, motors, etc.) which allow the printing head 45 to be translatedin the XYZ dimensions with respect to the component 18 during theprinting steps/operations.

By being adjustable in three dimensions, the stage 42 can translate thecomponent 18 and PCB 22 between the laser printing head 45 and curingmodule 34, and also adjust the displacements between and with respect tothe printing head 45 and the component 18, and between the curing module34 and the component 18. In addition, an inspection module 40 may beincluded in the system 46, and the stage 42 may be operable to positionthe component 18 and PCB 22 under the inspection module 40 prior to andbetween the printing and curing steps. For example, prior to a printingstep, the component 18 and PCB 22 can be inspected to aid in alignmentof the printing head 45 with respect to the component 18 and PCB 22.Following a printing and/or curing step, the component 18 and PCB 22 canbe inspected to determine whether any repair of a prior printing step isneeded.

The inspection module 40 may be configured to image and/or to measurethe topography of the component 18 and PCB 22 and/or may include opticalcomponents to permit real-time inspection by machine and/or humanoperators. The optical or other imaging inspection may reveal that whilemany of the droplets have been suitably printed on the component 18and/or PCB 22, some of the droplets are out of position or are otherwiseunsuitable. A controller 44 having access to this data may then operatethe system 46 so as to remediate the situation (e.g., removingimproperly printed material and having it reprinted, or havingadditional droplets printed to cover a gap, etc.). Imaging may beperformed before and/or after the material transfer by the laserprinting head 45 and may capture intermediate images during a printingstep.

In one embodiment of the invention, as depicted in FIG. 6 b , theinspection module 40 is positioned coincident with the printing head 45and a mirror 88 or other optical element (not depicted) may be employedto obtain images of the surface of the component 18 and/or PCB 22 duringthe jetting of the waterproof material 16. That is, the printing head 45may include a laser module 54 with an in-line inspection module 40. Asthe coated substrate 12 and/or component 18 is/are moved to a targetarea in the vicinity of the laser printing head 45, the laser module 54is activated to emit a laser beam 10 incident on the coated substrate 12in order to deliver the waterproof material 16 to the component 18. Theimages of the surface of the component 18 (obtained from the inspectionmodule 40) may be used to assist in alignment of the component 18 in thetarget printing area via the stage 42, as well as to help synchronizethe pulsing of the laser module 54. In some embodiments of theinvention, the laser module 54 of the printing head 45 may be configuredto scan the laser beam 10 in a raster-like pattern over the coatedsubstrate 12, releasing droplets of waterproof material 16 onto thecomponent 18. As indicated above, UV curing and/or drying can beperformed after the material 16 has been printed on the component 18.

Now referring to the side and top views of FIG. 4 e , once the printingof the waterproof material 16 at the edges 13 of the component 18 hasbeen completed, and that material 16 has been cured (if so desired),printing of the material 16 at other areas may commence. As shown, thisentails jetting (and/or spraying) droplets of the waterproof material 16from the coated substrate 12 to other areas of the component 18 thathave not been previously printed. In this example, the waterproofmaterial 16 is applied to the top surface of the component 18 (e.g., topsurface excluding the perimeter of the top surface). As indicated above,the volume of the droplets so printed may be determined by the energy ofthe laser 10 used for the jetting process, the thickness of the film 14of material coated on the transparent or semi-transparent substrate 12,or a combination of these parameters. Preferably, the droplet volume iscontrolled so as to ensure even distribution of the coating material 16on the component 18. This may be easiest with droplets of common volumethroughout the jetting process, but in some cases, the droplet volumemay be varied during the jetting process, for example, when componentfeatures demand or would benefit from the application of droplets ofdifferent volumes. The volume of the droplets printed during this partof the procedure may be the same as, larger than, or less than thedroplets printed during application of the waterproof material to theedges 13 of the component 18.

As shown in the side and top views of FIG. 4 f , the printing processcontinues with droplets of the waterproof material 16 being applied(e.g., by laser-induced jetting, laser-induced spraying, or both) to theareas of the PCB 22 surrounding the component 18. The volume of thedroplets printed during this part of the procedure may be the same as,larger than, or less than the droplets printed during application of thewaterproof material to the edges 13 of the component 18 and/or otherareas of the component 18. As discussed above, during this printingprocess, the component 18 and PCB 22 may be inspected so as to ensureall desired areas of the component 18 and PCB 22 are being coated withthe waterproof material 16. This printing step is followed, as shown inthe side and top views of FIG. 4 g , by a curing step during which thenewly printed droplets on the component 18 and PCB 22 are cured byexposure to UV light 36, heat, or both to form cured layers 38 of thematerial.

Optionally, an additional printing step may be performed as shown in theside and top views of FIG. 4 h . In this step, the component 18 and PCB22 are tilted with respect to the plane of the coated substrate 12 so asto allow for application of droplets of the waterproof material (bylaser-induced jetting, laser-induced spraying, or both) to areas of thecomponent 18 and/or PCB 22 that may have been missed during one of theprevious printing steps or which may have received a coating of lessthan a desired thickness. Such areas may include sharp corners, such aswhere the component 18 and PCB 22 are in close proximity to one another,or may include areas that may have been fully or partially masked byother portions of the component 18 or another component (not depicted)on the PCB 22 during one of the earlier printing steps. In theillustrated example, the component 18 and PCB 22 are tilted with respectto the plane of the coated substrate 12 (e.g., using a stage that can berotated about central point), but the reverse is also possible with theplane of the coated substrate 12 and the laser module 54 being tiltedwith respect to the component 18 and PCB 22. Printing in this fashion,with the component 18 and PCB 22 tilted with respect to the coatedsubstrate 12, can be used in any of above-described printing steps aswell. In such a titled arrangement, the bottom surface of the coatedsubstrate 12 may form an acute angle with respect to the top surface ofthe component 18 and/or PCB 22.

This optional printing step is followed, as shown in the side view ofFIG. 4 i , by a curing step during which the newly printed droplets onthe component 18 and/or PCB 22 are cured by exposure to UV light 36,heat, or both.

As is apparent from the foregoing discussion, aspects of the presentinvention involve the use of various computer systems and computerreadable storage media having computer-readable instructions storedthereon. For example, the processes described in the various figures maybe performed by a processor of the controller 44 executing a sequence ofinstructions that cause the processor to control inspection module 40,laser printing head 45 and curing module 34 in accordance with theprocesses described above.

FIG. 7 provides an example of system 100 that may be representative ofany of the computing systems (e.g., controller 44) discussed herein.Note, not all of the various computer systems have all of the featuresof system 100. For example, certain ones of the computer systemsdiscussed above may not include a display inasmuch as the displayfunction may be provided by a client computer communicatively coupled tothe computer system or a display function may be unnecessary. Suchdetails are not critical to the present invention.

System 100 includes a bus 102 or other communication mechanism forcommunicating information, and a processor 104 (e.g., a microcontroller,an ASIC, a CPU, etc.) coupled with the bus 102 for processinginformation. Computer system 100 also includes a main memory 106, suchas a random access memory (RAM) or other dynamic storage device, coupledto the bus 102 for storing information and instructions to be executedby processor 104. Main memory 106 also may be used for storing temporaryvariables or other intermediate information during execution ofinstructions to be executed by processor 104. Computer system 100further includes a read only memory (ROM) 108 or other static storagedevice coupled to the bus 102 for storing static information andinstructions for the processor 104. A storage device 110, for example ahard disk, flash memory-based storage medium, or other storage mediumfrom which processor 104 can read, is provided and coupled to the bus102 for storing information and instructions (e.g., operating systems,applications programs and the like).

Computer system 100 may be coupled via the bus 102 to a display 112,such as a flat panel display, for displaying information to a computeruser. An input device 114, such as a keyboard including alphanumeric andother keys, may be coupled to the bus 102 for communicating informationand command selections to the processor 104. Another type of user inputdevice is cursor control device 116, such as a mouse, a trackpad, orsimilar input device for communicating direction information and commandselections to processor 104 and for controlling cursor movement on thedisplay 112. Other user interface devices, such as microphones,speakers, etc. are not shown in detail but may be involved with thereceipt of user input and/or presentation of output.

The processes referred to herein may be implemented by processor 104executing appropriate sequences of computer-readable instructionscontained in main memory 106. Such instructions may be read into mainmemory 106 from another computer-readable medium, such as storage device110, and execution of the sequences of instructions contained in themain memory 106 causes the processor 104 to perform the associatedactions. In alternative embodiments, hard-wired circuitry orfirmware-controlled processing units may be used in place of or incombination with processor 104 and its associated computer softwareinstructions to implement the invention. The computer-readableinstructions may be rendered in any computer language.

In general, all of the above process descriptions are meant to encompassany series of logical steps performed in a sequence to accomplish agiven purpose, which is the hallmark of any computer-executableapplication. Unless specifically stated otherwise, it should beappreciated that throughout the description of the present invention,use of terms such as “processing”, “computing”, “calculating”,“determining”, “displaying”, “receiving”, “transmitting” or the like,refer to the action and processes of an appropriately programmedcomputer system, such as computer system 100 or similar electroniccomputing device, that manipulates and transforms data represented asphysical (electronic) quantities within its registers and memories intoother data similarly represented as physical quantities within itsmemories or registers or other such information storage, transmission ordisplay devices.

Computer system 100 also includes a communication interface 118 coupledto the bus 102. Communication interface 118 may provide a two-way datacommunication channel with a computer network, which providesconnectivity to and among the various computer systems discussed above.For example, communication interface 118 may be a local area network(LAN) card to provide a data communication connection to a compatibleLAN, which itself is communicatively coupled to the Internet through oneor more Internet service provider networks. The precise details of suchcommunication paths are not critical to the present invention. What isimportant is that computer system 100 can send and receive messages anddata through the communication interface 118 and in that way communicatewith hosts accessible via the Internet.

Thus, systems and methods that enable printing of conformal materialsand other waterproof coating materials at high resolution have beendescribed. Many other embodiments will be apparent to those of skill inthe art upon reviewing the above description. The scope of the inventionshould, therefore, be determined with reference to the appended claims,along with the full scope of equivalents to which such claims areentitled.

What is claimed is:
 1. A system, comprising: a laser-based printingsystem with a high frequency laser arranged to perform one or more oflaser-induced jetting and laser-induced spraying of a first materialonto an electronic component; a curing module configured to cure thefirst material with one or more of ultraviolet (UV) light and heat; anda controller comprising a processor and a memory storing instructionsthat, when executed by the processor, cause the processor to: controlthe laser-based printing system to, during a first printing step, printthe first material on edges of the electronic component by laser inducedspraying, wherein the laser induced spraying sprays droplets of thefirst material with a first droplet size onto the edges of theelectronic component; control the curing module to cure the firstmaterial printed during the first printing step; control the laser-basedprinting system to, during a second printing step, print the firstmaterial over portions of the electronic component excluding the edgesby laser induced jetting, wherein the laser induced jetting jetsdroplets of the first material with a second droplet size onto theportions of the electronic component excluding the edges, wherein thefirst droplet size is smaller than the second droplet size; and controlthe curing module to cure the first material printed during the secondprinting step.
 2. The system of claim 1, wherein the first material isjetted or sprayed from a layer of the first material coated on atransparent or semi-transparent substrate.
 3. The system of claim 2,further comprising a coating system that includes a screen-printingmodule configured to (i) coat the first material on a screen or stencilof film with well-defined holes and (ii) use a blade or a squeegee totransfer the first material to the transparent or semi-transparentsubstrate.
 4. The system of claim 2, further comprising a coating systemthat includes a dispenser or an ink jet head to print the first materialonto the transparent or semi-transparent substrate.
 5. The system ofclaim 2, further comprising a coating system that comprises a gravure ormicro-gravure system that coats the transparent or semi-transparentsubstrate with a uniform layer of the first material.
 6. The system ofclaim 2, further comprising a coating system that comprises a slot-diesystem that coats the transparent or semi-transparent substrate with auniform layer of the first material.
 7. The system of claim 2, furthercomprising a coating system that comprises a roller coating system thatcoats the transparent or semi-transparent substrate with a uniform layerof the first material.
 8. The system of claim 2, further comprising acoating system configured to coat the transparent or semi-transparentsubstrate with as a uniform layer of the first material, wherein thecoating system is disposed inside a closed cell with a controlledenvironment to prolong a pot life of the first material.
 9. The systemof claim 2, further comprising a coating system that contains a secondmaterial in addition to the first material, wherein the coating systemis configured to print the first and second materials onto thetransparent or semi-transparent substrate in a controlled sequence.